Reusable concrete form

ABSTRACT

Disclosed is a reusable, lightweight and rigid concrete forming tube made from fiberglass, injection molded plastic or similar material providing a surface with little tendency to adhere to the concrete. This makes it easy to remove the components and to reuse them without excessive cleaning required before the next use. Components are constructed with interlocking tabs so that assembly can be accomplished by merely inserting one male tab into a female opening in the corresponding tab in a slip fit relationship. Concrete or a similar material is poured into the top of the assembled tube. Upon hardening of the concrete, the tube is removed, leaving a formed concrete column of the desired cross sectional shape and length. After use the components are disassembled for use elsewhere.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

FIELD OF INVENTION

This disclosure relates to forms for molding settable materials such as concrete, polymer concrete, or the like and, in particular, to forms for molding concrete into columns and wherein the forms are made of interlocking sections.

BACKGROUND OF THE INVENTION

The invention is directed to a structural device for use in forming concrete into desired shapes. More specifically, the invention relates to a new and improved construction for a multi-use concrete forming device which can be assembled from component parts at a particular location, used to impart the desired shape to a semi-fluid concrete mixture, removed when the concrete has set, disassembled and moved to a new location of use.

As is well known, freshly mixed concrete must be retained in some type of forming device until it has hardened or “set” if it is to achieve the structural shape desired by the user known commonly as columns, piers and footings.

A number of methods in the past have been employed to do this. Among available forms are wood forms, spirally wrapped fiber forms (commonly referred to as paperboard), steel sectional forms and fiberglass forms.

Traditionally forms have been constructed from wood. Such material is reasonably inexpensive and is relatively easy to install. However, wooden forms are porous and frequently have rough surfaces. These factors create a tendency for concrete to adhere to the forms, not only sometimes making it difficult to remove them after the concrete has set, but also making it hard to reuse the form material, since portions of the surface often become partially coated with hardened cement. The need to frequently replace the forms, and the effort required to disassemble and remove them, creates an appreciable expense over time.

More recently fiber forms have become more common place for the forming of round concrete columns. Fiber forms are generally single piece cylindrical forms of a select diameter. The form can be cut to length on a job site, erected, braced and stripped relatively quickly and easily. These forms are not reusable as they are generally destroyed during the stripping process. They also leave helical seams on the finished concrete column. One other major problem is that using wound paper tubes as concrete forms subjects the tube to the exposure of an abundance of moisture. One example is when the poured concrete begins to set in a manner that urges its retained water to transfer either to the top or outwardly to the sides of the column form. As a result, paper tubes have not been very resistant against decay and deterioration when exposed to such excessive moisture conditions. This many times causes their delamination and in certain cases has actually resulted in failure of supporting the heavy poured concrete.

Early inventors tried to give consideration to the treatment of the paperboard tube for the purpose of achieving some sealing or even providing for an inner liner of polyethylene film. See United States patents such as the one to Atkinson, U.S. Pat. No. 2,316,752, to Copenhaver, U.S. Pat. No. 2,677,165, to Clarkson, U.S. Pat. No. 2,836,874 or to Hart, U.S. Pat. No. 2,914,833. The purpose of the teachings of these prior art patents was primarily to lend a quick release of the formed concrete from the interior of the paperboard tube column, and not so much from the standpoint of providing a water barrier for the tube itself. The problem with these proposed solutions is that after the concrete column had been formed and the tube rapidly removed, the polyethylene liner itself at times had to be delicately stripped from the formed columns, thereby necessitating an extra step in the process.

Other issues that occur with paper tubes is that by reason of the large diameter and length of such tubes, the transport, handling and storage of the tubes involve significant costs and inconvenience.

Steel forms generally comprise half round sections bolted into units. Each section comprises a semi-cylindrical wall framed with flange angles die cut and punched for flush butt joints. Vertical and horizontal seams are connected with bolts. Some of the problems with steel sectional forms include heavy weight, expensive production and the possibility of rusting steel as well as the same tendency to adhere to concrete that wooden forms have. Since they are expensive they cannot be discarded, but must be laboriously cleaned for reuse. This is a time consuming and costly process. Furthermore, metal objects heat rapidly in the sun, making it hard to handle the forms without severe discomfort. Steel forms are also heavy, hard to handle and their method of installation is often relatively intricate.

Fiberglass forms have also been used in half round sections as with steel form sections. However, fiberglass flanges require steel backing where bolts are used for securing sections together.

A concrete forming device has now been devised which has little tendency to adhere to concrete, making it easy to both remove the forms and reuse them with little further preparation. This device is lightweight, durable, water resistant and can be used repeatedly with great ease. The forming device is relatively cool to the touch, even after lying in strong sunlight for prolonged periods and therefore comfortable to work with. It is easily and quickly assembled, disassembled and transported. It can be permanently colored in bright, readily visible colors, assuring its easy visibility, resulting in increased safety. The concrete forming device hereinafter described is particularly useful in constructing concrete footings and piers such as those used in supporting decks and similar structures.

BRIEF SUMMARY OF THE INVENTION

It is, therefore, in view of prior art in existence respecting this invention in its preferred embodiment to provide as its principle object a reusable form that is particularly designed and contoured so as to provide for its easy and quick usage in forming poured concrete columns.

Another object of this invention in its preferred embodiment is to provide a form which is split into two longitudinal halves that can be easily shipped in their knockdown form and once again reassembled at the construction site into their tubular configuration making them ready for reception internally of any properly arranged reinforcing steel, if determined to be necessary, and an ample quantity of poured concrete thus facilitating its easy usage and assembly into a form for the constructing of concrete columns.

Another object of the present invention in its preferred embodiment is to provide a number of adequately formed joining tabs that interlock with each other to allow the form to hold its shape without separation thereby facilitating the constructing of concrete columns.

Another object of the present invention in its preferred embodiment is to provide a reusable concrete forming tube and a method of utilizing such a tube, wherein the transport, handling and storage of the tube is greatly facilitated with the attendant reduction in cost.

Another object of this invention in its preferred embodiment is to provide a device which is designed to furnish a moisture resistant form for pouring of concrete footings, piers, columns, or the like, and also provide for a quick release of the form from the concrete column after its setting.

Still another object of this invention in its preferred embodiment is to provide a concrete column form which permits the formation of concrete columns having any desired cross sectional shape such as circular, polygonal, square and the like.

A still further object of this invention in its preferred embodiment is to provide a concrete column form for forming concrete columns of any desired cross sectional shape which utilizes relatively inexpensive, readily available material, which may be manufactured in a simple and easy manner and at a high production rate, thus making the initial cost relatively low.

Still another Object of this invention in its preferred embodiment is to provide a concrete column form for forming concrete columns of any desired cross-sectional shape which is lightweight and rugged in construction; the inner surface of which permits the formation of a smooth uniform exterior on the poured concrete column and at the same time permits ready stripping of the form after hardening of the poured concrete column.

This invention in its preferred embodiment further contemplates the provision of a method and apparatus for forming such a concrete column form which permits the production of such forms of any desired length, required diameter and wall thickness which may be utilized at a high production rate to produce a form of relatively low cost.

These and other objects will become more apparent to those skilled in the art upon reviewing the summary of this invention and upon undertaking a study of the description of the preferred embodiment in view of its drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will be better understood when taken in conjunction with the drawings of the preferred embodiment of the invention. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the drawings:

FIG. 1 is an exploded view showing the two sections of the invention which make up the concrete form.

FIG. 2 is a perspective view of an assembled concrete column form utilizing sections according to the invention.

FIG. 3 is an enlarged view of the top interlocking tabs.

DETAILED DESCRIPTION OF THE INVENTION

In FIGS. 1 and 2 a column form is illustrated for molding a smooth, hard surface concrete column free of voids. The preferred embodiment is anticipated to be made from fiberglass, injection molded plastic or a material with similar characteristics thus furnishing a moisture resistant form for pouring of concrete footings, piers, columns, or the like, and also provide for a quick release of the form from the concrete column after its setting.

The two halves, simply referred to as Side A and Side B are assembled to each other to form a tubular configuration making them ready for reception internally of any properly arranged reinforcing steel, if determined to be necessary, and an ample quantity of poured concrete thus facilitating its easy usage and assembly into a form for the constructing of concrete columns.

The dimension of the form components, including diameter, wall thickness, height, width and length, may all be varied to meet the conditions of use and specified building codes. Typically these forms are round in shape and range from 8 to 14 inches in diameter and 48 to 72 inches in length. The wall thickness is typically 1/40^(th) the diameter of the form. This does not preclude other wall thicknesses, diameters, lengths or geometric shapes as desired or necessary.

As shown in FIG. 3 the invention contains two interlocking tabs located at the “top” of the invention. Specifically the top is the end where the handles for lifting and removing the invention are located. When the two sections are aligned as in FIG. 1 all tabs are fit together by interlocking the two opposing tabs on each side and then sliding them together in a downward motion to form a locking mechanism that prevents the form from becoming disengaged when the concrete is poured into the form as illustrated in FIG. 2. The top tabs also contain additional locking protrusions and channels to insure the form does not accidentally shift longitudinally. There are also holes molded into these tabs that will allow a bolt or piece of rebar to be placed through them to further insure there will be no longitudinal shift. With the use of these types of locking devices incorporated into the invention it is insured that the form will hold its shape until the concrete is sufficiently set to allow them to be easily removed.

The handles of the invention are designed to allow easy moving, placement into and removal of the invention from the excavation into which a footing is required. A secondary design consideration is to allow the handles to made to sufficient thickness as to allow them to rest upon the ground and provide the proper amount of concrete required to be exposed above the ground when the form is removed and the excavation filled in. This eliminates the need to set up additional measuring devices or guides.

Thus, with a concrete form such as is illustrated in FIG. 2 an interior space is provided which can be filled with concrete to construct a column, footing, pier, etc. Thereafter, the sections A and B can be disassembled and subsequently reused. The use of a form split longitudinally into two sections allows the same to be easily stacked with one another to facilitate transportation and storage.

Thus, in accordance with the invention, there is provided an inexpensive, reusable and lightweight mold form section.

While there has been described what at present is now considered to be the preferred embodiment of the invention and the principles thereof and considered to be the best mode contemplated for these principles, it will be understood by those skilled in the art that various changes and modifications may be made therein or similar principles used without departing from the invention. The above description is for purposes of illustration only and the invention is not intended to be limited by this description except as defined in the appended claims. It is the aim of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention. 

1. A form adapted for use in molding columns, footings, piers and the like made of concrete or similar materials into columns of any desired cross sectional shape and length including two interlocking sections secured together by a plurality of self aligning tabs and optionally by two bolts or pieces of rebar.
 2. The concrete column form of claim 1 wherein each section is comprised of a semi-cylindrical wall having a top edge with a handle centrally located on each, a bottom edge and opposite side edges with molded interlocking tabs.
 3. The concrete column form of claim 1 wherein the body of such form has sufficient rigidity to support a column of concrete mix poured therein.
 4. The concrete column form of claim 1 wherein adhesion of the mold walls to the cured concrete is prevented through the use of fiberglass, injection molded plastic or a similar material having similar properties preventing such adhesion.
 5. The concrete column form of claim 1 wherein each of the two said sections is formed in a unitary construction. 